#include <TinyWireM.h> //include the library
#define device (1) //define master
#define SLAVE_ADDRESS 0x6 //define the address for the slave

#include <SoftwareSerial.h>//add library to be able to use the serial monitor
int rxPin = 0; //the receiving pin
int txPin = 1; //the transmitting pin
SoftwareSerial serial(rxPin, txPin); // to set up the serial object

void setup() {
    TinyWireM.begin();//setup initialization
        
    pinMode(rxPin, INPUT); //the rx pin is the input of the communication
    pinMode(txPin, OUTPUT); //the tx pin is the output of the communication
    serial.begin(9600); //begin communication with computer
    }
    

void loop() {
    TinyWireM.beginTransmission(SLAVE_ADDRESS);//begin transmission to slave address
    TinyWireM.send(1);//send "1"
    TinyWireM.endTransmission();//end the transmission
    msg();//receive message
    delay(2000);//wait 2000 millisec

    TinyWireM.beginTransmission(SLAVE_ADDRESS);//begin transmission to slave address
    TinyWireM.send(0);//send "0"
    TinyWireM.endTransmission();//end the transmission
    msg();//receive message
    delay(2000);//wait 2000 millisec
    }

    void msg()
    {
    volatile byte msg =0; //treat as variable
    TinyWireM.requestFrom(SLAVE_ADDRESS,1);//request from slave address
  
    if (TinyWireM.available()){ //to make sure the master is available
    msg = TinyWireM.receive();//receive message
  
      if (msg ==4){//if this message
      serial.println("Slave LED off");}//print this in serial monitor
      else if (msg ==5){//if this message
      serial.println("Slave LED on");}//print this in serial monitor
      }
     }